Precautions For Maintenance

The hybrid system includes a high voltage circuit. Mishandling may cause electric shocks and leakage.

Therefore, perform proper operations by following procedures in this information.

CAUTION: Before working on a hybrid model, be sure to disconnect the ground terminal from the battery (12 V) to prevent burning and damaging caused by short circuit. Refer to REPAIR CONTENTS>REPAIR CONTENTS>NOTE>BATTERY>GROUND TERMINAL REMOVAL OR INSTALLATION .

High voltage caution display

Before working on a hybrid model, the vehicle should be marked with a caution sign.
Print this warning, fold along the perforation and put it on the roof of the vehicle in service before performing any service on the hybrid system.

HIGH VOLTAGE CAUTION LABEL

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Only technicians who have received the Subaru training for hybrid systems should be allowed to perform service or maintenance of high voltage circuits.
All the harnesses and connectors for high voltage power cable assemblies are colored in orange. In addition, caution labels indicating [Danger] and [Warning] are attached on the battery case. Do not touch the wiring and parts related to high voltage without proper Personal Protective Equipment (PPE) and extreme caution.
Personal Protective Equipment (PPE)
Always wear PPE which is in good condition when working on the hybrid system. Never touch any high voltage terminals or components without proper PPE.
Personal Protective Equipment consists of insulated rubber gloves, protective goggles, rubber boots or insulated protective shoes or insulating mat for the shop floor.
Always check the insulated gloves for holes or damage before starting work. To check for leaks, create a tight seal around your wrist with the glove gauntlet, and squeeze the glove to confirm that the trapped air does not leak, indicating a hole in the insulating material.

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Never use wet insulated gloves.

NOTE: Maintenance of the HV battery cooling fan and HV battery cooling duct outside the HV battery cover does not require you to wear PPE because the voltage is only 12 V. PPE is not required for maintenance or service of engine and CVT unit. However, orange-colored high voltage power cable assemblies are excluded.

Operation procedure

In addition to PPE, other precautions must be observed when working on the hybrid system since parts with high voltage and strong magnetic force are used.

Do not carry any metallic products, such as mechanical pencils and rulers, etc. They may be dropped and cause a short circuit.
Do not wear any metallic objects such as belts or buckles, chains, etc.
The strong magnetic force may adversely affect magnetic recording media (such as cash cards and prepaid cards), etc.
Always confirm that the voltage at any high voltage terminal is at 0 V using a circuit tester before beginning work.
To work on the high voltage wire connections, always use insulated tools.
Insulate the high voltage connectors and terminals with insulating tape immediately after removing.
Make sure to maintain the proper polarity of the positive and negative terminal connections during the HV battery removal and installation procedures.
Never connect the HV battery in reverse polarity. Otherwise, the control module will be broken instantly, and other parts will also be damaged.
Do not disconnect the battery cables while the engine is running. A large counter electromotive force will be generated, and this voltage may damage electronic parts such as control modules.
When disconnecting the connectors of the electrical components, always be sure to turn the ignition switch to OFF. Perform the clear memory for [Engine] after connecting the connectors. Refer to COMMON (DIAG)>CLEAR MEMORY .
When measuring the voltage or resistance of individual sensors or all electrical control modules, use a tapered pin with a diameter of 0.6 mm (0.02 in) or less and touch it to the tip of terminal. Never insert the tapered pin into the terminal because it deforms inside which may lead to malfunction.
Take care not to allow water to get into the connectors when servicing or washing the vehicle in rainy weather. Avoid exposure to water even if the connectors are waterproof.
Use the engine ground terminal or engine assembly for the grounding point when measuring the voltage and resistance in engine compartment.
All parts related to the hybrid system are precision parts. Do not drop or otherwise apply impact. Do not reuse the parts that are dropped accidentally.
Each warning light may illuminate during or after the diagnosis. However, this does not indicate a system malfunction. After the hybrid system diagnosis, perform Clear Memory Mode of [P-HEV Hybrid Powertrain Control]. Refer to COMMON (DIAG)>CLEAR MEMORY .
Take the access key out of the vehicle, except when the key is needed inside.
When the part is replaced or the label is detached, make sure to attach a new label in the original position and direction.

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This vehicle starts and stops the engine automatically, when the Hybrid READY indicator light in the meter illuminates. Make sure to turn the ignition switch to OFF before performing maintenance.

CAUTION:

Do not replace the battery ECM assembly and the engine control module (ECM) except when instructed in the diagnostics procedures.
When one of the units is replaced from another vehicle, the learning value may be overwritten by that of the high voltage battery with more severe damage, and information requesting the inspection and replacement of the high voltage battery may be displayed earlier.
Replacing the battery ECM assembly and the engine control module (ECM) at the same time will clear the learning value of the high voltage battery. Therefore, do not replace these parts at the same time. When it is necessary to replace both the battery ECM assembly and the engine control module (ECM), follow the procedures described below.

Procedures when replacing both the battery ECM assembly and the engine control module (ECM)

Disconnect the ground terminal from battery (12 V). Refer to REPAIR CONTENTS>REPAIR CONTENTS>NOTE>BATTERY .
Replace one of the units.
Connect the ground terminal to the battery (12 V). Refer to REPAIR CONTENTS>REPAIR CONTENTS>NOTE>BATTERY .
Turn to READY ON, and wait for 25 minutes or more.
Turn to IG OFF, and disconnect the ground terminal from the battery (12 V). Refer to REPAIR CONTENTS>REPAIR CONTENTS>NOTE>BATTERY .
Replace the other unit.
Connect the ground terminal to the battery (12 V). Refer to REPAIR CONTENTS>REPAIR CONTENTS>NOTE>BATTERY .
Confirm that it is possible to turn to READY ON.

NOTE:

If the battery ECM assembly and the engine control module (ECM) are replaced at the same time without performing the above procedures, put one of the units back to its original part before replacing, then follow the procedures described above. If the procedures were not properly followed, start from the beginning.
Learning value of the high voltage battery is recorded in the battery ECM assembly and in the engine control module (ECM) for displaying the message "Have high voltage battery inspected at retailer" on the multi-information display (MFD). If one of the units has been replaced, it receives the learning value data of the high voltage battery from the other unit and overwrites its information.